From 35fa23cbf139a87ba3dbcf1cce42b75a0a354cce Mon Sep 17 00:00:00 2001
From: diyelectromusic <68612569+diyelectromusic@users.noreply.github.com>
Date: Sat, 1 Apr 2023 15:35:00 +0100
Subject: [PATCH] Implement option to allow MIDI Program Change messages to
 select aross four consecutive banks as discussed in Issue #391. Note: It does
 not check if consecutive banks are loaded.  That is down to the user.  The
 default is "enabled".

---
 src/config.cpp    |  6 ++++++
 src/config.h      |  2 ++
 src/minidexed.cpp | 25 +++++++++++++++++++++++--
 src/minidexed.ini |  1 +
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/src/config.cpp b/src/config.cpp
index 44ac32f..c40d29a 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -72,6 +72,7 @@ void CConfig::Load (void)
 	m_bIgnoreAllNotesOff = m_Properties.GetNumber ("IgnoreAllNotesOff", 0) != 0;
 	m_bMIDIAutoVoiceDumpOnPC = m_Properties.GetNumber ("MIDIAutoVoiceDumpOnPC", 1) != 0;
 	m_bHeaderlessSysExVoices = m_Properties.GetNumber ("HeaderlessSysExVoices", 0) != 0;
+	m_bExpandPCAcrossBanks = m_Properties.GetNumber ("ExpandPCAcrossBanks", 1) != 0;
 
 	m_bLCDEnabled = m_Properties.GetNumber ("LCDEnabled", 0) != 0;
 	m_nLCDPinEnable = m_Properties.GetNumber ("LCDPinEnable", 4);
@@ -185,6 +186,11 @@ bool CConfig::GetHeaderlessSysExVoices (void) const
 	return m_bHeaderlessSysExVoices;
 }
 
+bool CConfig::GetExpandPCAcrossBanks (void) const
+{
+	return m_bExpandPCAcrossBanks;
+}
+
 bool CConfig::GetLCDEnabled (void) const
 {
 	return m_bLCDEnabled;
diff --git a/src/config.h b/src/config.h
index bc5e7c6..a316be8 100644
--- a/src/config.h
+++ b/src/config.h
@@ -78,6 +78,7 @@ public:
 	bool GetIgnoreAllNotesOff (void) const;
 	bool GetMIDIAutoVoiceDumpOnPC (void) const; // true if not specified
 	bool GetHeaderlessSysExVoices (void) const; // false if not specified
+	bool GetExpandPCAcrossBanks (void) const; // true if not specified
 
 	// HD44780 LCD
 	// GPIO pin numbers are chip numbers, not header positions
@@ -159,6 +160,7 @@ private:
 	bool m_bIgnoreAllNotesOff;
 	bool m_bMIDIAutoVoiceDumpOnPC;
 	bool m_bHeaderlessSysExVoices;
+	bool m_bExpandPCAcrossBanks;
 
 	bool m_bLCDEnabled;
 	unsigned m_nLCDPinEnable;
diff --git a/src/minidexed.cpp b/src/minidexed.cpp
index 6acda43..0bb7c14 100644
--- a/src/minidexed.cpp
+++ b/src/minidexed.cpp
@@ -413,13 +413,34 @@ void CMiniDexed::ProgramChange (unsigned nProgram, unsigned nTG)
 {
 	assert (m_pConfig);
 
-	nProgram=constrain((int)nProgram,0,31);
+	unsigned nBankOffset;
+	bool bPCAcrossBanks = m_pConfig->GetExpandPCAcrossBanks();
+	if (bPCAcrossBanks)
+	{
+		// Note: This doesn't actually change the bank in use
+		//       but will allow PC messages of 0..127
+		//       to select across four consecutive banks of voices.
+		//
+		//   So if the current bank = 5 then:
+		//       PC  0-31  = Bank 5, Program 0-31
+		//       PC 32-63  = Bank 6, Program 0-31
+		//       PC 64-95  = Bank 7, Program 0-31
+		//       PC 96-127 = Bank 8, Program 0-31
+		nProgram=constrain((int)nProgram,0,127);
+		nBankOffset = nProgram >> 5;
+		nProgram = nProgram % 32;
+	}
+	else
+	{
+		nBankOffset = 0;
+		nProgram=constrain((int)nProgram,0,31);
+	}
 
 	assert (nTG < CConfig::ToneGenerators);
 	m_nProgram[nTG] = nProgram;
 
 	uint8_t Buffer[156];
-	m_SysExFileLoader.GetVoice (m_nVoiceBankID[nTG], nProgram, Buffer);
+	m_SysExFileLoader.GetVoice (m_nVoiceBankID[nTG]+nBankOffset, nProgram, Buffer);
 
 	assert (m_pTG[nTG]);
 	m_pTG[nTG]->loadVoiceParameters (Buffer);
diff --git a/src/minidexed.ini b/src/minidexed.ini
index 2f5ce5b..27d622c 100644
--- a/src/minidexed.ini
+++ b/src/minidexed.ini
@@ -18,6 +18,7 @@ MIDIRXProgramChange=1
 IgnoreAllNotesOff=0
 MIDIAutoVoiceDumpOnPC=1
 HeaderlessSysExVoices=0
+ExpandPCAcrossBanks=1
 
 # HD44780 LCD
 LCDEnabled=1